<html>
  <style>
    h4 {
      width: 200px;
      height: 30px;
    }
    button {
      margin: 100px;
    }
  </style>
  <body>
    <h4>Title</h4>
    <button onclick='this.setAttribute("a", "ok")'>click me</button>
  </body>
</html>
